function makeBig(current) 
{
	//var id = current.id;
	var src = current.src;
	var indx1 = src.lastIndexOf('_');
	var indx2 = src.lastIndexOf('.');
	
	var first = src.substring(0, indx1 + 1);
	var last = src.substring(indx2, src.length);
	
	current.src = first + 'big' + last;	
}

function makeSmall(current) 
{
	var id = current.id;
	current.src = 'images/' + id + '_small.gif';	
}